1. Field of the Invention
The present invention relates generally to systems and methods which are used to analyze fluids which may or may not contain solid components. More particularly, the present invention relates to instruments and methods which are used in clinical laboratories and other healthcare locations to analyze blood and other bodily fluids.
2. Description of Related Art
Clinical chemistry involves the qualitative and quantitative analyses of body fluids, such as blood, urine, spinal fluid and other materials. Clinical chemistry encompasses multiple specialty testing areas including coagulation, hematology, immunochemistry, as well as chemistry. The test results derived from such analyses are used by physicians and other healthcare professionals to diagnose, monitor and treat diseases. The analysis protocols, instrumentation and other equipment utilized in clinical laboratory testing must be capable of providing accurate and repeatable test results. In addition, it is desirable that the procedures and instrumentation be simple and efficient. The testing equipment and procedures should be versatile enough that they can be used in healthcare locations where relatively few samples are tested as well as in larger clinical laboratories where the number of samples being tested on a daily basis is quite large.
Another consideration in designing analytical equipment for use by healthcare personnel is the amount of sample available for testing. In many situations, the amount of blood or other bodily fluid available is relatively small. Accordingly, there has been a trend in clinical chemistry to develop analytical systems which are capable of conducting numerous different chemical analyses on relatively small amounts of sample. In general, the goal has been to develop clinical analytical systems which provide the maximum number of medical tests utilizing the minimum amount of sample. In such systems, it is essential that the sample be accurately metered to provide a precise aliquot of sample for testing.
In achieving the above goals, a multitude of different analytical procedures and approaches have been investigated. In one approach, instruments have been developed which have a single sample introduction site. The equipment is designed so that the sample is split, metered and routed to various locations within the system where multiple chemical analyses take place. Other systems do not include internal sample splitting/metering devices and rely on the clinical chemist to separate the sample into small aliquots which are introduced into various instruments which are capable of conducting a maximum of only a few chemical analyses at one time.
There is a continuing need to develop and provide clinical chemistry instruments which are not only accurate, but versatile enough to meet the demands of modern medicine. The instruments should be simple enough to be used by not only highly-skilled laboratory technicians, but also by other healthcare personnel who may only be required to conduct laboratory tests intermittently. The instruments and procedures should be compact and versatile enough so that they can be utilized in clinical laboratories which analyze thousands of samples daily, while at the same time being adaptable to doctors"" offices, home healthcare agencies and nursing homes where the number of tests being conducted is not as great. In addition, the instruments should be versatile enough to be useful in conducting a wide variety of blood analyses which are presently being routinely utilized. The instruments should also be adaptable to conducting blood or other bodily fluid tests which will be developed in the future.
In accordance with the present invention, an analytical instrument is provided which is compact and versatile. The instrument is a xe2x80x9ccartridge-basedxe2x80x9d instrument in that it is designed to receive and process individual self-contained cartridges which are pre-loaded with sample and any required reagents. The instrument utilizes centrifugal force to process the test cartridges during the analysis process. The instrument is capable of simultaneously analyzing multiple test cartridges. The multiple test cartridges may be set up to conduct the same or different analytical tests. The instrument is extremely versatile because the cartridges are designed to carry out a wide variety of test protocols.
The instrument includes a cartridge carousel assembly which receives analytical cartridges. The cartridges are self-contained units which incorporate a sample metering/separation system which is operated by centrifugal force. The cartridge may also include a sample transport system which is operated by externally-applied pressure wherein the sample is transferred to a test element which provides a detectable analytical property of the fluid sample. The cartridge carousel is composed of a cartridge rotor plate which includes a center and a plurality of cartridge ports which are located in spaced relation radially outward from the center of the plate. The cartridge ports include a cartridge dock which is shaped to receive the cartridges and a balance weight dock which is located radially inward from the cartridge dock. The cartridge dock is shaped to receive a balance weight.
The cartridge carousel assembly further includes a rotary drive mechanism which rotates the cartridge rotor plate about the center thereof. It is this rotation of the cartridge rotor plate which operates the analytical system of the test cartridges. A locking mechanism is provided which holds the cartridge in the cartridge dock during rotation of the cartridge rotor plate. Further, a balancing mechanism is provided which comprises a balance weight wherein the balance weight is movable to the balance weight dock when a cartridge is inserted into the cartridge dock. The mechanism is designed so that the balance weight remains in the cartridge dock during rotation of the cartridge rotor plate if a cartridge is not present in the cartridge dock. In this way, the cartridge rotor plate is automatically balance regardless of the number of cartridges which are placed in the cartridge ports.
As a further feature of the present invention, an ejection mechanism is provided which ejects the test cartridge from the cartridge port after processing of the test cartridge is completed. A detector is included which measures detectable analytical properties of fluid samples exhibited by the test elements of the cartridges. Further, a tracking and control unit is provided which tracks and controls the rotary drive mechanism, locking mechanism and ejection system.
The analytical instrument in accordance with the present invention is well-suited for conducting a wide variety of clinical tests. The versatility of the instrument is only limited by the different types of test cartridges. The instrument is compact and simple to use. Accordingly, it can be used in a wide variety of settings ranging from large clinical laboratories which conduct thousands of tests daily to small hospital laboratories or doctors offices.
The above discussed features and attendant advantages of the present invention will become better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings.